apfs/linux-apfs
0
0
Fork 0
mirror of https://github.com/linux-apfs/linux-apfs.git synced 2026-05-01 15:00:59 -07:00
Code Issues Packages Projects Releases Wiki Activity

CRED: Use RCU to access another task's creds and to release a task's own creds

Browse Source 
Use RCU to access another task's creds and to release a task's own creds.
This means that it will be possible for the credentials of a task to be
replaced without another task (a) requiring a full lock to read them, and (b)
seeing deallocated memory.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
This commit is contained in:
David Howells
2008-11-14 10:39:19 +11:00
committed by James Morris
parent 86a264abe5
commit c69e8d9c01
28 changed files with 353 additions and 202 deletions
Download Patch File Download Diff File Expand all files Collapse all files
mm/mempolicy.c
+5 -3
View File
@@ -1110,7 +1110,7 @@ asmlinkage long sys_migrate_pages(pid_t pid, unsigned long maxnode,
const unsigned long __user *old_nodes,
const unsigned long __user *new_nodes)
{
struct cred *cred, *tcred;
const struct cred *cred = current_cred(), *tcred;
struct mm_struct *mm;
struct task_struct *task;
nodemask_t old;
@@ -1145,14 +1145,16 @@ asmlinkage long sys_migrate_pages(pid_t pid, unsigned long maxnode,
* capabilities, superuser privileges or the same
* userid as the target process.
*/
cred = current->cred;
tcred = task->cred;
rcu_read_lock();
tcred = __task_cred(task);
if (cred->euid != tcred->suid && cred->euid != tcred->uid &&
cred->uid != tcred->suid && cred->uid != tcred->uid &&
!capable(CAP_SYS_NICE)) {
rcu_read_unlock();
err = -EPERM;
goto out;
}
rcu_read_unlock();
task_nodes = cpuset_mems_allowed(task);
/* Is the user allowed to access the target nodes? */